I'm lone ump for Men's ASA SP game. 1 out, R1 on 2B, R2 on 1B. B1 hits a line drive between 1B and 2B. F3 lunges to his right, and the ball goes off his glove. Both baserunners had held up when they saw the ball hit directly at the fielder, but start running late when ball drops to the ground. F3 scrambles and picks up ball and throws to F6 who is running toward 2B. F6 crosses 2B in one swift motion towards 1B. F6's back foot leaves 2B just before he recieves the throw from F3, then F6 throws ball to F1 covering 1B, but B1 is already 20 feet past 1B. When F6 was making the pivot at 2B, R2 stopped just a few feet short of 2B, assuming he was about to be put out. I make no call on the play at 2B since R2 is not out (F6 did not have possession of the ball while in contact with the base), nor is he safe (R2 had not yet touched 2B). People start yelling and after a few seconds R2 realizes what's going on and makes it to 2B. Then I call him safe. Defensive coach asks me why it took me so long to make the call. I tell him that there was no call to make until R2 touched 2B, since before that, he was neither out nor safe. I think this seems pretty simple, but should I have done it any differently? Am I obliged to signal to either or both teams that F6 left the bag early while the play is still happening? Thanks in advance.

Delayed call
 

Seems correct to me...no call to make at the time. I've always been taught as a player, continue playing until you hear the call.

Great call. There is no call to make until R2 is out or safe. It's like R2 was still midway between the bases. Of course we can not make a cali, gotta wait. If you would have mentioned anything, then you may have shown bias to one of the teams.

Pretty much had the same play the other night. Good NO call.